In this paper, we simulate the mechanical behavior of coarse-grained polymeric composites, which have found wide application in engineering. One of the approaches to investigation of these materials is a structural cell approach. The results of modeling were obtained using the previously developed methods and some new approaches. We present here a methodology that can be applied to study deformation processes up to the failure of structural cells of a special type taking into account vacuole generation. The averaging procedure enabled us to make a transition to consideration of composite specimens (or mesoelements) by way of giving the character of random values to some parameters of cells. Use of these model specimens made it possible to examine the mechanical properties of coarse-grained elastomeric composites depending on such structural parameters. It is shown that the proposed approach provides the results, which are in good agreement with the experimental data.